"Put Darren Macnair at the top of our watch list."
Regulus's tone was calm as he laid out the plan. "For the next two nights, stay alert. If he makes a move after curfew, we follow."
Cuthbert nodded hard and thumped his fist against his knee.
Alex nodded too, smaller, but without hesitation this time.
"Remember," Regulus said, looking at both of them, "you follow my lead. If I say retreat, you retreat. No arguing. No delay."
"Understood," Cuthbert replied at once.
Alex gave a quiet, "Yeah."
---
That night, Regulus did not truly sleep. His mind hovered in the thin space between waking and dreams.
Every half hour, a faint prick pulsed along the inside of his left arm. The warning charm checking itself, confirming the link remained intact.
At one ten in the morning, the charm triggered.
Regulus's eyes snapped open.
He remained still for three seconds in the dark, confirming it was not a false alert. Then he sat up and called softly, "Cuthbert. Alex."
Rustling came from both beds at once. Cuthbert practically sprang upright. Alex was slower.
"There's movement outside," Regulus said, already reaching for his wand. "I'll check first. Be ready."
He did not wait for a reply. The tip of his wand tapped lightly against his chest. The Disillusionment Charm flowed over him.
The edges of his body blurred, warped, and then dissolved into the surrounding darkness.
When he eased the dormitory door open, he saw a figure standing near the exit of the Slytherin Common Room.
Darren Macnair.
He wore a pure black robe, the heavy fabric swallowing what little light there was.
In his right hand, he held a black wooden box about the size of a palm. The lid was shut tight.
Regulus stopped just inside the doorway, his breathing steady.
He extended his magical senses slowly toward Darren.
At five meters, he felt it.
A pulse of magic from within the box.
Ancient and dense.
Slow in rhythm, yet powerful.
It felt strikingly similar to the spell on the stone door beneath the Astronomy Tower.
More than similar. It felt like it shared the same root. Two branches from the same tree.
Regulus withdrew his senses and stepped back into the dormitory corridor.
As the Disillusionment Charm lifted from him, Cuthbert and Alex were already dressed, wands in hand.
Cuthbert's eyes gleamed in the dark. Alex's lips were pressed tight.
"It's Darren Macnair," Regulus said in a whisper. "He's carrying something. It resonates with the ward under the Astronomy Tower. He's moving tonight."
"Now we follow." Regulus raised his wand, pointing first at Cuthbert, then at Alex.
The improved Disillusionment Charm settled over them both.
They glanced down instinctively as their arms, torsos, and legs blurred and faded, until only the faintest translucent outlines remained. In dim light, they were almost impossible to distinguish. Only at close range could they see one another.
"Stay silent. Light steps. Stay close to me," Regulus said, renewing the charm on himself.
Cuthbert nodded. Alex followed suit.
They slipped into the Common Room.
Darren was already gone.
Regulus paused at the entrance, then slid into the corridor.
The hallway lay empty. Torches crackled along the walls, throwing long, wavering shadows.
About twenty meters ahead, a dark figure strode toward the staircase, robe hem flicking behind him.
"Follow."
Darren did not walk quickly, but his route was deliberate.
From the dungeon level housing the Slytherin Common Room, he turned into a narrow side passage rarely used, leading toward the abandoned classroom wing on the third floor east. Few portraits hung there, and at night it was nearly deserted.
Regulus kept roughly fifteen meters behind him. Cuthbert and Alex followed three steps behind Regulus. No footstep echoed. No breath betrayed them.
The modified Disillusionment Charm was far stronger than the standard version. It warped light, muffled sound, masked body heat, and suppressed stray magical leakage.
Regulus had not told the other two that. Knowing might make them careless.
They moved westward through the main body of the castle and mounted the spiral staircase that led toward the Astronomy Tower.
Moonlight slanted through the high windows, slicing silver and shadow across the steps.
Darren's shadow crawled along the wall. Every dozen steps or so, he paused and glanced back.
Regulus stopped before each turn, pressing himself into the deepest shadow. Cuthbert and Alex copied him, slipping into corners untouched by moonlight.
Darren continued, passing through a corridor lined with old portraits. The painted figures snored in uneven chorus.
Then he climbed another spiral flight leading to the western tower.
The Astronomy Tower.
They descended from there to the lower level and exited the castle grounds.
The wooden door at the base of the tower stood slightly ajar. Darren pushed it open. The hinges groaned in protest.
Regulus counted three heartbeats before slipping inside.
He lifted a hand, signaling the others to stop.
The abandoned instrument room smelled thick with dust. Moonlight spilled through broken windows, illuminating drifting particles in the air.
Darren was already at the far end, pushing aside the dead vines clinging to the stone wall.
The hidden entrance emerged. Black and hollow.
He hugged the box to his chest and bent to squeeze inside, movements slightly unsteady.
Regulus waited until Darren's footsteps receded into the passage, their echoes growing duller, then motioned Cuthbert and Alex forward.
The tunnel's damp earth scent was stronger inside, laced with moss.
Bioluminescent growth cast a faint green glow along the stone walls.
Darren's footsteps rang clearly ahead. He was not trying to hide. He likely believed no one would follow at this hour.
Regulus kept ten meters back, magical perception extended.
He could sense Darren's aura. Tight and uneven. The box pulsed with that abnormal resonance, harmonizing with the ancient runes carved into the stone walls.
They wound downward through turns and forks for quite some time.
When Darren reached the stone door, he stopped.
He raised his wand. A pale light flared at the tip, illuminating the twisted runes carved into the surface.
Under the glow, the characters seemed almost alive, shifting faintly against the stone.
Darren studied them for a few seconds, then opened the box.
Inside, dark-purple velvet lined the interior. At the center lay a crystal the size of a fist.
Within the crystal, a mass of gray mist churned slowly.
Faces formed and dissolved within it. Distorted features. Mouths stretched wide in silent screams.
Darren inhaled sharply, his chest rising and falling hard. He lifted the crystal with both hands and held it straight out before the stone door.
He spoke the first word.
The language was ancient and rough. The syllables dragged from deep in his throat, each one heavy, striking the air like a stone dropped into water.
The gray mist inside the crystal began to spin faster.
Regulus halted at a bend in the passage, holding Cuthbert and Alex back.
He raised his left hand, fingers spread. Magic gathered in his palm, ready to form his modified Protego, a filtering lattice.
He had only recently completed the theoretical structure.
It worked by identifying magical properties, blocking only malicious or curse-laden fluctuations while allowing neutral magic to pass through.
Its advantage was precision. It filtered out lethal elements others might overlook.
Its weakness was the extreme control required.
He could manage it.
He did not know what lay behind the door. Hermes's curse was proof enough of the danger.
He was not here for reckless adventure. He was here to observe, gather information, and confirm the enemy's identity.
If the situation spiraled beyond control, retreat would be the first choice.
Curiosity had its place.
But you only had one life. That lesson he had learned long ago.
Darren's chanting quickened. The ancient words seemed to take on substance, each syllable sending ripples through the air. The ripples struck the stone walls and rebounded, weaving complex echoes through the tunnel.
The runes on the stone door began to glow.
First a dim red.
Then deep purple.
Finally, they solidified into an ominous gray-black.
The gray mist inside the crystal boiled.
It slammed against the inner walls. Fine cracks spread across the crystal's surface like a web.
Sweat beaded on Darren's forehead and slid down his temples. His fingers turned white around the crystal. His arms trembled.
He clenched his teeth so hard a faint grinding sound escaped him.
Then he forced out the final, drawn-out syllable.
The sound lingered in the tunnel for three full seconds.
The stone door shuddered.